The ethmoid sinuses or ethmoid air cells of the
ethmoid bone are one of the four paired
paranasal sinuses. The cells are variable in both size and number in the
lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral examination. They are divided into anterior and posterior groups.
The ethmoid air cells are numerous thin-walled cavities situated in the
ethmoidal labyrinth
The ethmoidal labyrinth or lateral mass of the ethmoid bone consists of a number of thin-walled cellular cavities, the ethmoid air cells, arranged in three groups, anterior, middle, and posterior, and interposed between two vertical plates of bon ...
and completed by the
frontal
Front may refer to:
Arts, entertainment, and media Films
* ''The Front'' (1943 film), a 1943 Soviet drama film
* ''The Front'', 1976 film
Music
* The Front (band), an American rock band signed to Columbia Records and active in the 1980s and e ...
,
maxilla
The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
,
lacrimal,
sphenoidal
The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the or ...
, and
palatine bones. They lie between the upper parts of the
nasal cavities
The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal c ...
and the
orbits
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...
, and are separated from these cavities by thin bony lamellae.
Groups of sinuses
The groups of the ethmoidal air cells drain into the nasal meatuses.
[Otorhinolaryngology, Head and Neck Surgery, Anniko, Springer, 2010, page 188]
* The posterior group the ''posterior ethmoidal sinus'' drains into the
superior meatus
In anatomy, the term nasal meatus can refer to any of the three meatuses (passages) through the skulls nasal cavity: the superior meatus (''meatus nasi superior''), middle meatus (''meatus nasi medius''), and inferior meatus (''meatus nasi inferi ...
above the
middle nasal concha; sometimes one or more opens into the
sphenoidal sinus
The sphenoid sinus is a paired paranasal sinus occurring within the within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012 ...
.
* The anterior group the ''anterior ethmoidal sinus'' drains into the
middle meatus of the
nose
A nose is a protuberance in vertebrates that houses the nostrils, or nares, which receive and expel air for respiration alongside the mouth. Behind the nose are the olfactory mucosa and the sinuses. Behind the nasal cavity, air next passes ...
by way of the
infundibulum An infundibulum (Latin for ''funnel''; plural, ''infundibula'') is a funnel-shaped cavity or organ.
Anatomy
* Brain: the pituitary stalk, also known as the ''infundibulum'' and ''infundibular stalk'', is the connection between the hypothalamus an ...
.
The two groups are divided by the basal lamella. This is one of the bony divisions of the ethmoid bone and is mostly contained inside the
ethmoid labyrinth. Medially the lamella becomes the bony part of the middle concha.
Development
The ethmoidal cells (sinuses) and maxillary sinuses are present at birth.
Innervation
The ethmoidal air cells receive sensory fibers from the anterior and posterior
ethmoidal nerves
The ethmoidal nerves, which arise from the nasociliary nerve, supply the ethmoidal cells; the posterior branch leaves the orbital cavity through the posterior ethmoidal foramen and gives some filaments to the sphenoidal sinus. There are two ethm ...
, and the orbital branches of the
pterygopalatine ganglion, which carry the
postganglionic
In the autonomic nervous system, fibers from the ganglion to the effector organ are called postganglionic fibers.
Neurotransmitters
The neurotransmitters of postganglionic fibers differ:
* In the parasympathetic division, neurons are ''chol ...
parasympathetic nerve fibers for
mucous secretion from the
facial nerve
The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste ...
.
Haller cell
Haller cells are infraorbital ethmoidal air cells lateral to the
lamina papyracea
The orbital lamina of ethmoid bone, (or lamina papyracea or orbital lamina) is a smooth, oblong bone plate which forms the lateral surface of the labyrinth of the ethmoid bone in the skull.
The plate covers in the middle and posterior ethmoidal ...
. These may arise from the anterior or posterior ethmoidal sinuses.
Pathology
Acute ethmoiditis in childhood and ethmoidal carcinoma may spread superiorly causing meningitis and cerebrospinal fluid leakage or it may spread laterally into the orbit causing
proptosis and
diplopia
Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often v ...
.
[Human Anatomy, Jacobs, Elsevier, 2008, page 210]
Additional images
File:Slide2ROMA.JPG, Ethmoid sinus. Ethmoidal air cells.Deep dissection. Superior view.
File:Diagram showing ethmoid sinus cancer that has spread to the lymph nodes CRUK 121.svg, Ethmoid sinus cancer that has spread to the lymph nodes
References
External links
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Bones of the head and neck